sensiory philosophy

Cornea

The clear covering over the front of the eye through which light enters.

Iris

The colored part of the eye that regulates the size of the pupil.

Pupil

The central opening of the iris that controls the amount of light entering the eye.

Aqueous humor

The clear fluid-filled space between the lens and cornea that provides nutrients and regulates eye pressure.

Vitreous humor

A transparent gel-like tissue that fills the posterior chamber of the eye and provides structure.

Ciliary muscles

Muscles attached to the lens that change its shape for focusing images onto the retina.

Retina

The layer of the eye composed of a pigmented layer and a neural layer containing photosensitive cells.

Rods and cones

Photosensitive cells in the retina that are stimulated by light; rods for low light and cones for color vision.

Fovea

A depression in the retina where rods and cones are most densely packed, providing sharp vision.

Optic nerve

Transmits visual information from the retina to the brain.

Optic disc

The region of the retina where the optic nerve exits, containing no photosensitive cells.

Choroid

A layer of vascular tissue at the back of the eye that supplies nutrients.

Sclera

A tough connective tissue layer that protects the eye.

Pinnae

The outer part of the ear that collects sound waves.

Tympanic membrane (eardrum)

Vibrates in response to sound waves, transmitting vibrations to the middle ear bones.

Cochlea

A fluid-filled structure in the inner ear where sound vibrations are converted to nerve impulses.

Semicircular canals

Fluid-filled tubes in the inner ear responsible for balance and equilibrium.

Eustachian tube

Regulates pressure in the middle ear and connects to the pharynx.

Mechanoreception

The detection of physical forces; includes sensations of temperature, pain, pressure, and touch.

Merkel’s discs

Receptors in the skin that provide information about objects continuously touching the skin.

Meissner’s corpuscles

Receptors that provide information about changes in objects touching the skin.

Ruffini endings

Cutaneous receptors that provide information about low-frequency vibrating stimuli.

Pacinian corpuscles

Receptors that react to high-frequency alternating stimuli, such as rough surfaces.

Reflex arc

A neural pathway that controls a reflex action, consisting of a receptor neuron, sensory neuron, and motor neuron.

Pupillary reflex

An unconscious reflex that controls the size of the pupil in response to light.